The post that I'm in the process of making will be a 16" tall, 3" square aluminum extrusion attached to a 10" square, 1/4" aluminum plate with screws from the bottom and reinforced aluminum brackets. The plate will be secured to the cockpit sole by through bolts at the corners, sandwiched to another 10" plate under the sole. A bb swivel base with cam cleat and ratchet block will be mounted on the top of the post on a 1/4" plate capping the post.
I thought about "outriggers" to brace each side of the post against the side of the cockpit, but my shins are in pretty bad shape so I nixed that idea in favor of the reinforced angle brackets. My concern is for flexing of the cockpit sole. As far as I can tell, the sole is in good shape, no soft spots, etc.
I'm inclined to attach the main sheet tackle directly between the post and the boom, for sake of simplicity, if nothing else. I've never sailed a boat with a main sheet traveler so maybe I don't know what I'm missing so with that in mind, I'll probably try it both ways. Since I'm used to sailing with the down wind hand on the tiller and the upwind hand on the main sheet, I'm trying to maintain my comfort zone.
Thanx for the pix, everyone. Any more is appreciated....
Tom G